1. Field of the Invention
The present invention is generally related to optical devices and methods such as those used for surgery. In particular the present invention relates to techniques for enhancing the throughput and manipulation of optical information through a limited cross-section endoscopic relay. In one aspect, the invention provides an endoscope having an optical relay, objective, or ocular using at least one intermediate image formed within an optical component such as a glass element or lens. In another aspect, the invention provides an ocular system that permits independent adjustment of the diopters, magnification, X-Y positioning and rotational orientation of an image, while introducing minimal aberrations.
Minimally invasive medical techniques are aimed at reducing the amount of extraneous tissue which is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. The average length of a hospital stay for a standard surgery is significantly longer than the average length for the equivalent surgery performed in a minimally invasive surgical manner. Patient recovery times, patient discomfort, surgical side effects, and time away from work are also reduced with minimally invasive surgery.
The most common form of minimally invasive surgery may be endoscopy Probably the most common form of endoscopy is laparoscopy, which is minimally invasive inspection and surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient's abdomen is insufflated with gas, and cannula sleeves are passed through small (approximately ½ inch) incisions to provide entry ports for laparoscopic surgical instruments.
The laparoscopic surgical instruments generally include a laparoscope for viewing the surgical field, and working tools defining end effectors. To perform surgical procedures, the surgeon passes these working tools or instruments through cannula sleeves to a desired internal surgical site and manipulates the tools from outside the abdomen. The surgeon often monitors the procedure by means of a television monitor which displays an image of the surgical site via the laparoscopic camera. Similar endoscopic techniques are employed in, e.g., arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy, hysteroscopy, urethroscopy, and the like.
Minimally invasive telesurgical systems are now being developed to increase a surgeon's dexterity, so that the surgeon performs the surgical procedures on the patient by manipulating master control devices to control the motion of servomechanically operated instruments. In such a telesurgery system, the surgeon is again provided with an image of the surgical site via an endoscope. In both telesurgical and manual endoscopic procedures, the endoscope may optionally provide the surgeon with a stereoscopic image to increase the surgeon's ability to sense three-dimensional information regarding the tissue and procedure.
Endoscopes typically include three optical sub-systems: an objective lens system, an ocular lens system, and a relay lens system. The objective lens system is located at the distal portion of the endoscope to capture the desired image. The ocular lens system or eyepiece is located at the proximal portion of the endoscope and generally remains outside the patient body to transmit the desired image to the eye, camera, or the like. The relay lens system is generally disposed between the objective and ocular to transfer the image proximally out of the patient along a relatively small diameter endoscope shaft.
The objective lens system is typically separated from the relay system by an objective-relay air gap, while the relay system is separated from the ocular lens system by a relay-ocular air gap. The relay will typically be separated into a series of relay lens units, with the relay units again being separated by gaps. The objective lens system generally forms a first intermediate image in the objective-relay gap. The relay lens system then transfers this intermediate image from the distal portion of the scope toward the proximal portion by generating as many intermediate relay images as appropriate to travel the length of the shaft. A last intermediate image is produced by the relay system in the relay-ocular gap. The ocular collimates or nearly collimates this final intermediate image for detection by a surgeon's eye via viewing lenses such as an eyepiece, or for transmission to the imaging optics of a camera, the camera optics typically forming a final image on a charge couple device (CCD) of the camera.
The ocular lens system of known monoscopic endoscopes typically has a plurality of lenses that can manipulate the captured image. The optical properties of the captured image can be modified to ensure proper viewing of the desired object within the body. While such adjustments may be adequate for monoscopic endoscopes, when imaging a target site with a stereo imaging optics, it is of particular importance to have very accurate adjustments between the stereo channels to provide accurate three dimensional information that can be matched between the two channels. If accurate matching is not accomplished, the stereo viewer will provide an inaccurate image and may cause eye strain for the user.
While these known monoscopic endoscopic structures and methods have been quite successful, and are now widely used for imaging of internal tissues and surgical sites via minimally invasive apertures, further improvements would be desirable. In general, it would be desirable to provide improved optical systems and methods. It would be particularly desirable if these improved optical techniques enhanced the amount of optical information which could be transmitted along an optical path having a given, relatively limited cross-section (and/or diminished the cross-section to transmit a given image). It would further be desirable to provide improved monoscopic and stereoscopic endoscopes with enhanced image quality and/or decreased cross-sectional dimensions for use in manual and robotic minimally invasive surgical procedures. Additionally, it would further be desirable to provide an ocular system which allows independent adjustment of the optical properties of the image, while limiting the amount of aberrations introduced. Moreover, it would further be desirable to provide endoscopes which have the sensitivity in its adjustments to allow matching (e.g., position, orientation, size, and simultaneous focus) of the left and right channels of a stereo endoscope.
2. The Background Art
The following U.S. patents may be related to the present invention, and the full disclosures of each is hereby incorporated herein by reference: U.S. Pat. Nos. 5,568,312; 5,743,846; 5,743,847, 5,776,049; 5,861,987; and 5,956,179.
Robotic surgical systems which might make use of the improved imaging capabilities of the present invention are described in the following, each of which is incorporated herein by reference: U.S. patent application Ser. No. 09/378,173; filed Aug. 20, 1999; Ser. No. 09/433,120, filed Nov. 3, 1999; and Ser. No. 09/418,726, filed Oct. 15, 1999.